Alkyl vinyl ether/N-arylmaleimide copolymer containing polymer alloy

ABSTRACT

A thermodynamically miscible polymer composition containing a copolymer having recurring units of an alkyl vinyl ether and recurring units of an N-aryl substituted maleimide and an acrylonitrile copolymer is disclosed.

This invention relates to polymer compositions.

In one of its more specific aspects this invention pertains tothermodynamically miscible polymer compositions containing a copolymerof an alkyl vinyl ether with an N-aryl substituted maleimide monomer andan acrylonitrile copolymer.

The miscibility of polymers is generally determined using differentialscanning calorimetry to measure glass transition temperature. Athermodynamically miscible polymer composition will exhibit a singleglass transition temperature value which typically lies intermediatebetween the glass transition temperatures of the individual polymericcomponents. Correspondingly, a partially miscible or immisciblecomposition will exhibit two or more glass transition temperaturevalues. Accordingly, two or more polymers are thermodynamically misciblewhen a mixture of the polymers results in a material exhibiting asingle, well defined glass transition temperature.

Quite surprisingly, it has been found that within certain proportions acopolymer of an alkyl vinyl ether with an N-aryl substituted maleimideis thermodynamically miscible with a styrenic/acrylonitrile copolymer.

According to this invention there is provided a polymer compositioncomprising (A) a copolymer having from about 40 to about 60 mole % of analkyl vinyl ether and from about 60 to about 40 mole % of an N-arylsubstituted maleimide and (B) a polymer selected from the groupconsisting of (1) a copolymer matrix of from about 65 to about 85% byweight of a vinyl aromatic monomer selected from the group consisting ofstyrene and α-methylstyrene and from about 15 to about 35% by weightacrylonitrile, and (2) a rubber grafted with a copolymer matrix of fromabout 65 to about 85% by weight of a vinyl aromatic monomer selectedfrom the group consisting of styrene and α-methylstyrene and from about15 to about 35% by weight acrylonitrile wherein the weight ratio ofcomponent (A) to the copolymer matrix of component (B) is from 99:1 to1:99; and wherein component (A) and the copolymer matrix of (B) arethermodynamically miscible with one another such that the polymercomposition exhibits a single glass transition temperature value.

According to this invention, there is also provided a method ofproducing a molded composition which comprises forming a compositioncomprising (A) a copolymer having from about 40 to about 60 mole % of analkyl vinyl ether and from about 60 to about 40% by weight of an N-arylsubstituted maleimide and (B) a polymer selected from the groupconsisting of (1) a copolymer matrix of from about 65 to about 85% byweight of a vinyl aromatic monomer selected from the group consisting ofstyrene and α-methylstyrene and from about 15 to about 35% by weightacrylonitrile, and (2) a rubber grafted with a copolymer matrix of fromabout 65 to about 85% by weight of a vinyl aromatic monomer selectedfrom the group consisting of styrene and α-methylstyrene, and from about15 to about 35% by weight acrylonitrile and wherein the weight ratio ofcomponent (A) to the copolymer matrix of component (B) is from 99:1 to1:99, and wherein component (A) and the copolymer matrix of (B) arethermodynamically miscible with one another such that the polymercomposition exhibits a single glass transition temperature value, andmolding the resulting composition.

Also, according to this invention there is provided a molded compositioncomprising a single continuous phase, the single continuous phase beinga polymer composition comprising (A) a copolymer having from about 40 toabout 60 mole % of an alkyl vinyl ether and from about 60 to about 40mole % of an N-aryl substituted maleimide and (B) a copolymer matrix offrom about 65 to about 85% by weight of a vinyl aromatic monomerselected from the group consisting of styrene and α-methylstyrene andfrom about 15 to about 35% by weight acrylonitrile.

According to this invention there is also provided a molded compositioncomprising a continuous phase and a disperse phase within the continuousphase, the continuous phase being a polymer composition comprising (A) acopolymer having from about 40 to about 60 mole % of an alkyl vinylether and from about 60 to about 40 mole % of an N-aryl substitutedmaleimide and (B) a copolymer matrix of from about 65 to about 85% byweight of a vinyl aromatic monomer selected from the group consisting ofstyrene and α-methylstyrene, and from about 15 to about 35% by weightacrylonitrile, the disperse phase being a rubber which is grafted withsaid copolymer matrix (B). When reference is made to the weight of thecopolymer matrix of (B) it is to be understood that the weight of anyrubber is to be excluded.

As the alkyl vinyl ether component of (A) use can be made of C1 to C18alkyl vinyl ethers and mixtures thereof. Suitable alkyl vinyl ethersinclude methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether,isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether,t-butyl vinyl ether, n-amyl vinyl ether, isoamyl vinyl ether, t-amylvinyl ether, n-hexyl vinyl ether, n-heptyl vinyl ether, n-octyl vinylether, isoctyl vinyl ether, 2-ethylhexyl vinyl ether, decyl vinyl ether,dodecyl vinyl ether (laurel vinyl ether), tetradecyl vinyl ether,hexadecyl vinyl ether (ethyl vinyl ether), octadecyl vinyl ether, ormixtures thereof. Isobutyl vinyl ether is the preferred alkyl vinylether.

The N-aryl substituted maleimide of component (A) can beN-phenylmaleimide, N-tolylmaleimide, N-(chlorophenyl) maleimide,N-(bromophenyl) maleimide and the like, and their mixtures. Thepreferred N-aryl substituted maleimide is N-phenylmaleimide.

The preferred component (A) copolymer composition is from about 40 toabout 60 mole % alkyl vinyl ether and from about 60 to about 40% byweight N-aryl substituted maleimide.

The peak molecular weight of the component (A) copolymer as measured bygel permeation chromatography (vs a monodisperse polystyrene standard)should be within the range of from 50,000 to about 500,000. The mostpreferred peak molecular weight range is from about 70,000 to about150,000.

Examples of suitable component (B) materials include ABS(acrylonitrile-poly(butadiene)-styrene terpolymer) AES(acrylonitrile-EPDM-styrene terpolymer), SAN (styrene-acrylonitrilecopolymer) and the like and their mixtures. The preparation of therubber grafted (ABS or AES) polymers is well known and is incorporatedin this invention by reference to U.S. Pat. Nos. 3,509,237; 3,509,238;3,851,014; 3,903,200; 4,471,092 and 4,476,283. The preferred compositionof component (B) is a rubber, either polybutadiene or EPDM, grafted witha copolymer having from 72 to 80% by weight of a vinyl aromatic monomerand 20 to 28% by weight of acrylonitrile. The vinyl acromatic monomer incomponent (B) can be either styrene or α-methylstyrene, however, mostpreferred is styrene.

The polymer composition of this invention will comprise from about 99 toabout 1% by weight of component (A) and from about 1 to about 99% byweight of the copolymer matrix of component (B) excluding the weight ofthe rubber, if present. Preferrably the polymer composition willcomprise from 1 to 25 weight % of component (A) and from 99 to 75 weight% of the polymer matrix of component (B). If the rubber grafted with acopolymer matrix is selected ad component (B), the amount of rubberutilized will be from about 1 to about 40 parts by weight per 100 partsof the copolymer matrix of (B), that is, the vinyl aromatic plus theacrylonitrile.

The polymer composition can be prepared using any suitable method ofblending such as, for example, melt mixing or reaction blending.Reaction blending involves, for example, dissolving an already formedalkyl vinyl ether/N-aryl substituted maleimide copolymer in a mixture ofstyrene monomer and acrylonitrile monomer followed by incorporation of afree radical initiator and copolymerization of the styrene andacrylonitrile monomers.

Evaluation of material properties was performed based on the followingASTM standard tests: flexural modulus (D-790), tensile strength (D-638),elongation (D-638), notched Izod (D-256) and DTUL (deflectiontemperature under load), 1/8" at 264 psi, (D-648). Glass transitiontemperature was determined by differential scanning calorimetry (DSC).

EXAMPLE 1

This example demonstrates the preparation of an isobutyl vinylether/N-aryl substituted maleimide suitable for use in the practice ofthis invention.

A solution of about 126.7 grams of N-phenylmaleimide in 600 millilitersof isopropyl acetate was prepared in a mixing vessel.

Next, the solution was transferred into a one liter stirred reactor atroom temperature under a nitrogen atmosphere.

Into the reactor were charged about 83.3 grams of isobutyl vinyl etherand 0.4 gram of azoisobutyronitrile (Vazo 64 initiator, E. I. DuPont) tobegin the polymerization. The polymerization reaction was carried out at60° C. for about 4 hours. The resultant copolymer was isolated byprecipitation in methanol and dried in a vacuum oven at 100° C. forabout 4 hours. About 165 grams of isobutyl vinyl ether/N-phenylmaleimidecopolymer was recovered.

The copolymer was tested and found to contain 72.9 weight %N-phenylmaleimide (% nitrogen determination) with the balance beingisobutyl vinyl ether. The copolymer was also found to possess a glasstransition temmperature (DSC) of 193° C. and a peak molecular weight ofabout 132,000 as measured by gel permeation chromatography (vs amonodisperse polystyrene standard).

The copolymer was also subjected to thermal gravametric analysis in bothoxygen and nitrogen atmospheres. The results of the static thermal testsare set forth in following Table I.

                  TABLE I                                                         ______________________________________                                                 Copolymer Weight Loss %                                              Atmosphere 1%           5%      50%                                           ______________________________________                                        Oxygen     300° C.                                                                             350° C.                                                                        390° C.                                Nitrogen   300° C.                                                                             335° C.                                                                        400° C.                                ______________________________________                                    

EXAMPLE 2

This example demonstrates the thermodynamic miscibility of a polymercomposition of this invention.

Equal amounts of the isobutyl vinyl ether/N-phenylmaleimide copolymerprepared in Example 1 and a styrene/acrylonitrile copolymer designatedLustran® SAN-33 (32.2 wt % acrylonitrile) by Monsanto Chemical Company,were combined by dissolving both copolymers in tetrahydrofuran followedby precipitation in methanol. The resulting polymer composition wasdried in a vacuum oven at 90° C. until a constant weight was reached.

Following Table 2 compares the individual glass transition temperaturesof each above copolymer with the glass transition temperature of theircomposition. For the composition according to the invention (PolymerComposition), the data show a single well defined glass transitiontemperature intermediate between the glass transition temperatures ofthe copolymer components (A) and (B).

                  TABLE 2                                                         ______________________________________                                                                Tg (°C.)                                       ______________________________________                                        Isobutyl vinyl ether/N--  193                                                 phenylmaleimide copolymer (A)                                                 SAN-33 (styrene/acrylonitrile                                                                           109                                                 copolymer) (B)                                                                Polymer Composition (C)(50 wt % A/50 wt % B)                                                            128                                                 ______________________________________                                    

EXAMPLE 3

This example demonstrates the preparation of three polymer compositionsof this invention using the isobutyl vinyl ether/N-phenylmaleimideprepared according to Example 1 and a styrene/acrylonitrile copolymerdesignated Lustron® SAN-31 (23.4 wt. % acrylonitrile) by MonsantoChemical Company. Substantially the method of Example 2 was used withthe exception that the copolymers were individually combined in amountsto give three polymer compositions containing 25, 50 and 75 weightpercent isobutylene/N-phenylmaleimide, respectively. Following Table 3shows the glass transition temperature values of each composition ascompared to the glass transition temperatures of the individualcopolymer components.

                  TABLE 3                                                         ______________________________________                                                   Composition (wt %)                                                 ______________________________________                                        Isobutyl vinyl ether/                                                                      --      25      50    75    100                                  N--phenylmaleimide                                                            copolymer                                                                     Lustran ® SAN-31                                                                       100     75      50    25    --                                   Tg(DSC)      109° C.                                                                        120° C.                                                                        142° C.                                                                      165° C.                                                                      193° C.                       ______________________________________                                    

EXAMPLE 4

This example demonstrates the thermodynamic miscibility of a polymercomposition of this invention.

About 20 grams of the isobutyl vinyl ether/N-phenylmaleimide copolymerprepared in Example 1 and about 30 grams of ABS designated CyrolacL-1000 by Borg-Warner Company, were combined by melt blending in aBrabender at about 460° F. for about 5 minutes.

Following Table 4 compares the individual glass transition temperaturesof each above copolymer with the glass transition temperature of theircomposition. For the composition according to the invention (PolymerComposition), the data show a single well defined glass transitiontemperature intermediate between the glass transition temperatures ofthe copolymer components (A) and (B).

                  TABLE 4                                                         ______________________________________                                                           Tg (°C.)                                            ______________________________________                                        Isobutyl vinyl ether/N--                                                                           193                                                      phenylmaleimide copolymer (A)                                                 CYCROLAC L-1000      106                                                      Borg-Warner (B)                                                               Polymer Composition  132                                                      (40 wt % A/60 wt % B) (C)                                                     ______________________________________                                    

EXAMPLE 5

The example demonstrates the useful physical properties, particularlyheat distortion temperature, obtained from a polymer composition of thisinvention which contains 10 parts of an isobutyl vinylether/N-phenylmaleimide copolymer prepared following substantially theprocedure of Example 1, and 100 parts of the Cycolac L-1000 ABS. Thecopolymers were combined using the procedure of Example 4, extruded intopellets and the pellets injection molded into test specimens. Table 5shows the physical properties obtained as compared to the physicalproperties of the molded ABS resin alone.

                  TABLE 5                                                         ______________________________________                                        ABS.sup.1             100     100                                             Isobutyl Vinyl Ether/                                                                            10 phr  --                                                 N--PMI (Example 1)                                                            Extrusion Temp.    460° F.                                                                        460° F.                                     Pyromelt           460° F.                                                                        460° F.                                     Tg(°C., DSC)                                                                                 118     106                                             Tensile Str (psi)   5,490   5,160                                             Flex Str. (psi)    246,000 235,000                                            Tensile Mod (psi)  188,000 172,100                                            DTUL (1/8", °F.)                                                                             183     167                                             GFWI (in-lbs)         240      320+                                           Notched Izod (ft-lbs/in)                                                                         6.0     9.1                                                ______________________________________                                    

It will be evident from the foregoing that various modifications can bemade to this invention. Such, however, are considered as being withinthe scope of the invention.

What is claimed is:
 1. A polymer composition comprising (A) a copolymerhaving from about 40 to about 60 mole % of at least one C₁ to C₁₈ alkylvinyl ether and from about 60 to about 40 mole % of at least one N-arylsubstituted maleimide, said component (A) having a peak molecular weightof from about 50,000 to about 500,000 and (B) a polymer selected fromthe group consisting of (1) a copolymer matrix of from about 65 to about85% by weight of a vinyl aromatic monomer selected from the groupconsisting of styrene and α-methylstyrene and from about 15 to about 35%by weight acrylonitrile, and (2) a rubber grafted with a copolymermatrix of from about 65 to about 85% by weight of a vinyl aromaticmonomer selected from the group consisting of styrene andα-methylstyrene, and from about 15 to about 35% by weight acrylonitrilewherein the weight ratio of component (A) to the copolymer matrix ofcomponent (B) is from 99:1 to 1:99; wherein if component (B) (2) isemployed, the rubber will be present in an amount of from about 1 toabout 40 parts per each 100 parts of the copolymer matrix; and whereincomponent (A) and the copolymer matrix of (B) are thermodynamicallymiscible with one another such that the polymer composition exhibits asingle glass transition temperature value.
 2. The polymer composition ofclaim 1 in which said N-aryl substituted maleimide of component (A) isselected from the group consisting of at least one of N-phenylmaleimide,N-tolymaleimide, N-(chlorophenyl) maleimide and N-(bromophenyl)maleimide.
 3. The polymer composition of claim 1 in which said alkylvinyl ether of component (A) is selected from the group consisting of atleast one of methyl vinyl ether, ethyl vinyl ether, n-propyl vinylether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether,t-butyl vinyl ether, n-amyl viny ether, isoamyl vinyl ether, t-amylvinyl ether, n-hexyl vinyl ether, n-heptyl vinyl ether, n-octyl vinylether, isoctyl vinyl ether, 2-ethylhexyl vinyl ether, decyl vinyl ether,dodecyl vinyl ether (laurel vinyl ether), tetradecyl vinyl ether,hexadecyl vinyl ether (ethyl vinyl ether), octadecyl vinyl ether, ormixtures of these.
 4. The polymer composition of claim 1 in whichcomponent (A) is a copolymer of recurring units of isobutyl vinyl etherand N-phenylmaleimide.
 5. The polymer composition of claim 1 in whichthe component (A) copolymer has a peak molecular weight within the rangeof from about 50,000 to about 500,000.
 6. The polymer composition ofclaim 1 in which the component (A) copolymer has a peak molecular weightwithin the range of from about 70,000 to about 150,000.
 7. The polymercomposition of claim 1 in which said component (B) is anacrylonitrile-poly(butadiene)-styrene terpolymer.
 8. The polymercomposition of claim 1 in which said component (B) is anacrylonitrile-EPDM-styrene terpolymer.
 9. The polymer composition ofclaim 8 in which said component (B) is a styrene-acrylonitrilecopolymer.
 10. The polymer composition of claim 1 in which saidcomponent (B) is an acrylonitrile-poly(butadiene)-methylstyreneterpolymer.
 11. The polymer composition of claim 1 in which saidcomponent (B) is an acrylonitrile-EPDM-α-methylstyrene terpolymer. 12.The polymer composition of claim 1 in which said component (B) is aα-methylstyrene-acrylonitrile copolymer.
 13. The polymer composition ofclaim 1 in which the weight ratio of component (A) to the copolymermatrix of component (B) is from 25:75 to 1:99.
 14. A method of producinga molded composition which comprises forming a composition comprising(A) a copolymer having from about 40 to about 60 mole % of at least oneC₁ to C₁₈ alkyl vinyl ether and from about 60 to about 40 mole % of atleast one N-aryl substituted maleimide, said component (A) having a peakmolecular weight of from 50,000 to about 500,000 and (B) a polymerselected from the group consisting of (1) a copolymer matrix of fromabout 65 to about 85% by weight of a vinyl aromatic monomer selectedfrom the group consisting of styrene and α-methylstyrene and from about15 to about 35% by weight acrylonitrile and (2) a rubber grafted with acopolymer matrix of from about 65 to about 85% by weight of a vinylaromatic monomer selected from the group consisting of styrene andα-methylstyrene, and from about 15 to about 35% by weight acrylonitrile,wherein the weight ratio of component (A) to the copolymer matrix ofcomponent (B) is from 99:1 to 1:99; wherein if component (B) (2) isemployed the rubber will be present in an amount of from about 1 toabout 40 parts per each 100 parts of the copolymer matrix; and whereincomponent (A) and the copolymer matrix of (B) are thermodynamicallymiscible with one another such that the polymer composition exhibits asingle glass transition temperature value, and molding the resultingcomposition.
 15. A molded composition comprising a single continuousphase, the single continuous phase being a polymer compositioncomprising (A) a copolymer having from about 40 to about 60 mole % of atleast one C₁ to C₁₈ alkyl vinyl ether and from about 60 to about 40 mole% of at least one N-aryl substituted maleimide, said component (A)having a peak molecular weight of from 50,000 to about 500,000 and (B) acopolymer matrix of from about 65 to about 85% by weight of a vinylaromatic monomer selected from the group consisting of styrene andα-methylstyrene and from about 15 to about 35% by weight acrylonitrile.16. A molded composition comprising a continuous phase and a dispersephase within the continuous phase, the continuous phase being a polymercomposition comprising (A) a copolymer having from about 40 to about 60mole % by weight of at least one C₁ to C₁₈ alkyl vinyl ether and fromabout 60 to about 40 mole % of at least one N-aryl substitutedmaleimide, said component (A) having a peak molecular weight of from50,000 to about 500,000, and (B) a copolymer matrix of from about 65 toabout 85% by weight of a vinyl aromatic monomer selected from the groupconsisting of styrene and α-methylstyrene, and from about 15 to about35% by weight acrylonitrile, the disperse phase being a rubber which isgrafted with said copolymer matrix (B).